Scroll compressor is a compressor in which a compression chamber continuously moving between a fixed wrap and an orbiting wrap while an orbiting scroll performs orbiting movement with respect to a fixed scroll in a state that the fixed wrap of the fixed scroll is engaged with the orbiting wrap of the orbiting scroll is formed to inhale and compress refrigerant.
The scroll compressor continuously performs inhalation, compression and discharge, and thus has excellent characteristics in terms of vibration and noise generated during its operational process compared to other types of compressors.
The behavior characteristic of a scroll compressor is determined by its type of the fixed wrap and orbiting wrap. The fixed wrap and orbiting wrap may have an arbitrary shape, but typically have an involute curved shape that can be easily processed. The involute curve denotes a curve corresponding to a trajectory drawn by a cross section of thread when unloosing thread wound around a base circle having an arbitrary radius. When using such an involute curve, the capacity change rate is constant because a thickness of the wrap is constant and thus the number of turns should be increased to obtain a high compression ratio, but in this case, there is a drawback of increasing the size of the compressor at the same time.
On the other hand, for the circular scroll, an orbiting wrap is typically formed at one side of a disk-shaped end plate and a boss portion is formed at a rear surface on which the orbiting wrap is not formed and connected to a rotation shaft for orbiting the circular scroll. Such a shape may form an orbiting wrap over a substantially overall area of the end plate, thereby decreasing a diameter of the end plate portion for obtaining the same compression ratio. However, on the contrary, the operating point to which a repulsive force of refrigerant is applied and the operating point to which a reaction force for cancelling out the repulsive force is applied are separated from each other in an axial direction, thereby causing a problem of increasing vibration or noise while the behavior of the circular scroll is unstabilized during the operational process.
As a method for solving such problems, there is disclosed a so-called shaft penetration scroll compressor in which a position at which the rotation shaft 1 and the circular scroll 2 are coupled to each other is formed on the same surface as that of the orbiting wrap 2a. In such a shaft penetration scroll compressor, the operating point of a repulsive force and the operating point of the reaction force are applied at the same position, thereby solving a problem that the circular scroll 2 is inclined.